1. Field of the Invention
The present invention relates to a method and apparatus for image forming, and more particularly to a method and apparatus for image forming that prevents the use of unsuitable process cartridges at a relatively low cost.
2. Discussion of the Background
Many image forming apparatuses such as copying machines, facsimile machines, printers and so forth, incorporate a so-called "process cartridge," which includes toner or ink as well as associated components for image processing. Typically, the process cartridge is detachably installed in the imaging forming apparatus in order to facilitate an operation for exchanging the cartridge or supplying toner (or ink) relative to the cartridge.
Each of these apparatuses is generally configured to accept a process cartridge which is specifically designed for it and to refuse other process cartridges. The reason for this is that the electrostatic image forming method using toner (or ink) requires techniques so delicate that the manufacturers of image forming apparatuses uniquely develop the toner, or the ink. Accordingly, by use of an incorrect process cartridge, (i.e., a process cartridge not specifically designed for use in a particular image forming apparatus) problems associated with quality of an image may arise, or the image forming apparatus may be damaged.
To avoid such a problem, many solutions have been developed. One exemplary technique is described in Japanese Laid Open Patent Publication No. 08-106207 (1996). This technique provides a toner tank portion of an image forming apparatus with projections corresponding to depressions provided to a specific toner cartridge so as to select only a specific toner cartridge. In this case, however, if the projections and/or the depressions are removed for any reason, the image forming apparatus may easily accept any cartridge even those which are incorrect.
Another exemplary technique is described in Japanese Laid Open Patent Publication No. 09-185254 (1997). This technique provides an image forming apparatus with a drive gear which meets only with a driven gear of a specific process cartridge so as to select only the specific process cartridge. In this case, however, the shape of the diverse gear for each type of the image forming apparatus is changed, and thus, the manufacturing cost may increase.
Therefore, it is believed that there is no image forming apparatus available which includes a reparable mechanism for preventing the use of unsuitable process cartridges at a relatively low cost.